You have the ability to save content to your personal library that can be synced with your other devices. There is also a 'board' which will present you with recommendations relating to your library as well as any notifications that may arise.
Stremio allows you to easily import content from Facebook and your local disk. It also has some readily available add-ons that can be used to enhance the overall experience - the real gem here, in my opinion, is 'Guidebox' which allows you to view movies and TV shows from Hulu, Netflix, iTunes and others. You can also elect to see videos from the numerous Youtube channels out there.... Like the MajorGeeks channel for instance.
Stremio features the ability to watch instantly in HD by just clicking and playing your favorite movies, television shows, videos, and TV channels, automatic subtitles, casting to AppleTV, Chromecast, Smart TV's, mobile devices and more.